Process of making bricks or bodies for refractory linings or other uses and the product thereof.



UNITED STATES Patented July 21, 1903.

P TENT OFFICE.

ERNST WILHELM ENGELS, OF DUSSELDORF, GERMANY.

PROCESS OF MAKING BRICKS OR BODIES FOR REFRACTORY LININGS OR OTHER USESAND THE PRODUCT THEREOF.

SPECIFICATION forming part of Letters Patent No. 734,458, dated July 21,1903.

Original application filed March 8, 1900, Serial No. 7,817. Divided andthis application filed February 11, 1903. Serial No. 142,927. (Nospecimens.) 7

1i) all whom it may concern:

Be it known that I, ERNST WILHELM EN- GELS, a citizen of Germany,residing at Dusseldorf, Germany, have invented certain new and usefulImprovements in Processes of Making Bricks or Bodies for RefractoryLinings and other Uses and the Product Thereof, of which the followingis a specification.

This invention relates to the processes of making bricks orbodies forrefractory linings and other uses and the product thereof; and theobjects and advantages of the same will appear hereinafter.

This application is a division and continuation of my originalapplication filed March 8,1900, Serial No. 7,817.

It has been proposed heretofore to use carbid of silicon or carborundummixed with a binding agent, which in a plastic mass is molded intosuitable form and subsequently dried to produce a homogeneous structureof that material.

So far as I am aware, it is new in the present invention to employcarborundum as a coating for a less refractory body, exemplified bybrick, and applied in the manner to be hereinafter stated.

It is the main object of the present invention to provide a refractorycoating or covering of a homogeneous nature for fire-bricks or otherrefractory bodies which is so applied to the brick or body as that afterthe firing or burning of the brick the coating or covering will behighly tenaeionsthat is to say, it adheres so firmly to and is soincorporated in the surface of the brick or body that it will notreadily crack or separate therefrom. This is due to the physicalqualities of the carborundum coating, and it is extremely strong and notbrittle.

Oarborundum in the form of a coating or covering in accordance with thepresent invention efiiciently protects the inner core, is absolutelyproof against and excludes the pyrochemical action of gases, it is notinfluenced injuriously by changes of temperature, and it is insensibleto flying ashes, and therefore cannot form an objectionable slag, and inconsequence of these advantages carbid of silicon or carborundum asapplied in the present process to form a coating is the ideal, as wellas the most practical, material for this purpose. v

For the carrying out of the present process the plastic or soft materialof which the body of the fire-brick or other refractory article isproduced'is first formed up in a mold or in any other suitable manner toproduce the plates or articles to be coated, and then with the. surfaceof the plate, brick, or other article there is intimately united beforeburning a coating or covering of carbornndum, either by rubbing thecarbid in or by direct pressure, thereby causing the carbid to adhere toand be impressed into the surface without resorting to any bindingmaterial. It is evident that no bindingmaterial is necessitated, becausethe finely-divided carbid is applied to the surface while the brick orrelatively.

the physical condition of the carborundum,.

which has not as yet been recognized for this purposenamely, the factthat much manufactured carborundum is produced in the finely-dividedcondition, which readily facompared with other fireproof materials ofwhich I am aware carborundum can be used in a very thin layer.

The described composite brick produced before firing by the describedprocess when it is subjected to high temperature is furnished with arefractory surface of exceeding hardness, which is intimatelyincorporated with the brick or body and does not readily crack orseparate therefrom. Indeed the carbid seems to unite or blend with thesubstance of the brick, although carborundum is not known to be fusibleby itself at the temperatures involved in furnaces, and it washeretofore supposed that the use of the electric arc was necessary tocause the carborundum to'unite with the brick.

Ice

I am aware that it is old to mold bricks, retorts, crucibles, and otherfire-ware receptacles, which have been dusted with powdered calomine,(an oxid and not a carbid,) the bricks themselves being formed of smallpieces of flint and an aluminous binding material, these bricks beingsubjected to the heat of the kiln, in consequence of which the calominewill be fused and act as a flux on the surface of the brick. This isWidely distinguished from the present invention by the fact that in thepresent process the carborundum is not an oxid and does not by itselffuse and form a flux, but, on the contrary, is more refractory than thebrick into whose surface it is embedded. The article produced by thepresent invention is still more widely distinguished, because thecarborundum in the surface is less fusible than the interior of thebrick itself, whereas in the case of the calomine-coated articles thereverse is true.

I am also aware that it has been proposed to produce spotted or mottledefiects on bricks by incorporating triassic red shale with the surfaceof an ordinary brick or block of clay in order that when it is subjectedto the proper degree of heat the fusible portions of the shale-likeSubstance will be melted within and on the surface of the brick, whichitself does not melt, and will form the veins, spots, or protuberancesthat give the mottled effect; but this is not the object of thepresentinvention. Nor does the surface coating formed with carborundumas I have described melt in any such Way as does the surface of redshale described in the Lenderoth Patent No. 508,428.

I am also aware thatit has been proposed or grains that areincorporatedwith the body;

but here again the metallic powder or grains are relatively more fusiblethan the body of the material to which they are applied.

Having thus described my invention and distinguished the same from whatis old prior thereto, What I claim as new, and desire to secure byLetters Patent, is-

1. The process of producing bricks or bodies for refractoryfurnace-linings or other uses, which consists in applying to the surfaceof unburned brick, while in a plastic state, carborundum, and forcingthe carborundum into the surface by pressure, before firing the saidbrick orbody,and subsequently firing orburning the said brick or body ata temperature less than that of the electric are for producing a highlyrefractory surface which does not readily crack or separatefrom the lessrefractory and more fusible interior portion, substantially asdescribed.

2. As a new product, a brick or body con- .sisting essentially offire-brick but having at and near one or more of its surfacescarborundum impressed and incorporated superficially into the substanceof the brick itself in contradistinction to an enamel such as is formedby the electric arc.

In testimony whereof I have signed this specification in the presence oftwo subscribing witnesses.

ERNST WILl-IELM ENGELS.

Witnesses:

PETER LIEBER, WILLIAM ESSENWEIN.

